Chapter 17 Gate Drive Unit (GDUV4)
MC9S12ZVM Family Reference Manual Rev. 1.3
626
Freescale Semiconductor
17.2
External Signal Description
17.2.1
HD — High-Side Drain Connection
This pin is the power supply for the 3-phase bridge (DC-link voltage).
NOTE
The HD pin should be connected as near as possible to the drain connections
of the high-side MOSFETs.
17.2.2
VBS[2:0] — Bootstrap Capacitor Connection Pins
The pins are the bootstrap capacitor connections for phases HS[2:0]. The capacitor is connected between
HS[2:0] and this pin. The bootstrap capacitor provides the gate voltage and current to drive the gate of the
external power FET.
17.2.3
HG[2:0] — High-Side Gate Pins
The pins are the gate drives for the high-side power FETs. The drivers provide a high current with low
impedance to turn on and off the high-side power FETs.
17.2.4
HS[2:0] — High-Side Source Pins
The pins are the source connection for the high-side power FETs and the drain connection for the low-side
power FETs. The low voltage end of the bootstrap capacitor is also connected to this pin.
17.2.5
VLS[2:0] — Voltage Supply for Low-Side Pre-Drivers
The pins are the voltage supply pins for the three low-side FET pre-drivers. This pins should be connected
to the voltage regulator output pin VLS_OUT. The output voltage on VLS_OUT pin is typically
V
VLS
=11V.
NOTE
It is recommended to add a 110nF-220nF X7R ceramic capacitor close to
each VLS pin.
17.2.5.1
LG[2:0] — Low-Side Gate Pins
The pins are the gate drives for the low-side power FETs. The drivers provide a high current with low
impedance to turn on and off the the low-side power FETs.
17.2.5.2
LS[2:0] — Low-Side Source Pins
The pins are the low-side source connections for the low-side power FETs. The pins are the power ground
pins used to return the gate currents from the low-side power FETs.
